HEP Phenomenology·hep-ph

Mon·Sep 17, 2018Monday·September 17, 2018

16 papers—11 primary·5 cross-listed·reconstructed*

01*
The past, present and future of the heavier electroweakinos in the light of LHC and other data
Amitava Datta🇮🇳 · Nabanita Ganguly🇮🇳
The aim of this paper is to showcase the novel multilepton ( $n l + E /_{T}$ , n = 3 - 5) signals, hitherto unexplored at the LHC, arising from the heavier electroweakinos, in several generic pMSSMs at the upcoming LHC experiments. We first briefly review our old constraints on the full electroweakino sector of these models, containing both lighter and heavier sparticles, using the ATLAS trilepton data from the LHC Run I. Next we derive new stronger constraints on this sector for the first time using the ATLAS Run II data. We identify some benchmark points and explore the prospect of observing multilepton events in future LHC experiments. Our focus is on the channels with $n > 3$ which are the hallmarks of the heavier electroweakinos. If the spectrum of the lighter electroweakinos is compressed, these signals might very well be the discovery channels of the electroweakinos at the high luminosity LHC. We also discuss the implications of the new LHC constraints for the observed dark matter relic density of the universe, the measured value of the anomalous magnetic moment of the muon and the dark matter direct detection experiments.
hep-phJHEP(2019)·10 citations
02*
NLO and NNLO corrections to polarized top quark decays
Stefan Groote🇪🇪 · Jürgen G. Körner🇩🇪
We present partial results on NLO and NNLO QCD, and NLO electroweak corrections to polarized top quark decays. In parallel we derive positivity bounds for the polarized structure functions in polarized top quark decays and check them against the perturbative corrections to the structure functions.
hep-phEPJ Web Conf.(2018)·0 citations
03*
Holographic description of total hadronic cross sections at high energies
Akira Watanabe🇨🇳 · Mei Huang🇨🇳
We investigate the hadron-hadron total cross sections at high energies in the framework of holographic QCD. In our model setup, the involved strong interaction is described by the Brower-Polchinski-Strassler-Tan Pomeron exchange kernel, and the two form factors are obtained from the bottom-up AdS/QCD models. We show that the resulting nucleon-nucleon total cross section is consistent with the experimental data recently measured by the TOTEM collaboration at the LHC. As examples to see the general versatility of the model, we also present our analysis on the pion-nucleon and pion-pion cases, which can be predicted because all the adjustable parameters are fixed by the nucleon-nucleon data.
hep-phnucl-thEPJ Web Conf.(2018)·0 citations
04*
Intriguing feature of multiplicity distributions
M. Rybczyński🇵🇱 · G. Wilk🇵🇱 · Z. Włodarczyk🇵🇱
Multiplicity distributions, P(N), provide valuable information on the mechanism of the production process. We argue that the observed P(N) contain more information (located in the small N region) than expected and used so far. We demonstrate that it can be retrieved by analysing specific combinations of the experimentally measured values of P(N) which we call {it modified combinants, Cj, and which show distinct oscillatory behavior, not observed in the usual phenomenological forms of the P(N) used to fit data. We discuss the possible sources of these oscillations and their impact on our understanding of the multiparticle production mechanism.
hep-phnucl-thEPJ Web Conf.(2019)·3 citations
05*
Two-loop massless QCD corrections to the $g + g \to H + H$ four-point amplitude
Pulak Banerjee🇮🇳 · Sophia Borowka🇨🇭 · Prasanna K. Dhani🇮🇳 · Thomas Gehrmann🇨🇭 · V. Ravindran🇮🇳
We compute the two-loop massless QCD corrections to the four-point amplitude $g + g \to H + H$ resulting from effective operator insertions that describe the interaction of a Higgs boson with gluons in the infinite top quark mass limit. This amplitude is an essential ingredient to the third-order QCD corrections to Higgs boson pair production. We have implemented our results in a numerical code that can be used for further phenomenological studies.
hep-phhep-thJHEP(2018)·42 citations
06*
From $D_{s}^{\pm}$ production asymmetry at the LHC to prompt $ν_{τ}$ at IceCube
Victor P. Goncalves🇧🇷 · Rafal Maciula🇵🇱 · Antoni Szczurek🇵🇱
The description of the heavy meson production at large energies and forward rapidities at the LHC is fundamental to derive realistic predictions of the prompt atmospheric neutrino flux at the IceCube Observatory. In particular, the prompt tau neutrino flux is determined by the decay of $D_{s}$ mesons produced in cosmic ray - air interactions at high energies and large values of the Feynman - $x_{F}$ variable. Recent data from the LHCb Collaboration indicate a production asymmetry for $D_{s}^{+}$ and $D_{s}^{-}$ mesons, which cannot be explained in terms of the standard modelling of the hadronization process. In this paper we demonstrate that this asymmetry can be described assuming an asymmetric strange sea ( $s (x) \neq = s ˉ (x)$ ) in the proton wave function and taking into account of the charm and strange fragmentation into $D_{s}$ mesons. Moreover, we show that the strange quark fragmentation contribution is dominant at large - $x_{F}$ ( $\geq 0.3$ ). The prompt $ν_{τ}$ flux is calculated and the enhancement associated to the strange quark fragmentation contribution, disregarded in previous calculations, is estimated.
hep-phastro-ph.HEhep-exPLB(2019)·10 citations
07*
Sbottoms as probes to MSSM with nonholomorphic soft interactions
Utpal Chattopadhyay🇮🇳 · AseshKrishna Datta🇮🇳 · Samadrita Mukherjee🇮🇳 · Abhaya Kumar Swain🇮🇳
Presence of nonholomorphic soft SUSY breaking terms is known to be a possibility in the popular setup of the Minimal Supersymmetric Standard Model (MSSM). It has been shown that such a scenario known as NonHolomorphic Supersymmetric Standard Model (NHSSM) could remain `natural' ( i.e., not fine-tuned) even in the presence of a rather heavy higgsino-like LSP. However, it turns out that distinguishing such a scenario from the MSSM is unlikely to be an easy task, in particular at the Large Hadron Collider (LHC). In a first study of such a scenario at colliders (LHC), we explore a possible way that focuses on the sbottom phenomenology. This exploits the usual $tan β$ -dependence (enhancement) of the bottom Yukawa coupling but reinforced/altered in the presence of non-vanishing nonholomorphic soft trilinear parameter $A_{b}^{'}$ . For a given set of masses of the sbottom(s) and the light electroweakinos (LSP, lighter chargino etc.) which are known from experiments, the difference between the two scenarios could manifest itself via event rate in the 2b-jets + $\neq E_{T}$ final state, which could be characteristically different from its MSSM expectation. Impact on the phenomenology of the stops at the LHC is also touched upon.
hep-phhep-exJHEP(2018)·11 citations
08*
Factorisation and Subtraction beyond NLO
Lorenzo Magnea🇮🇹 · Ezio Maina🇮🇹 · Giovanni Pelliccioli🇮🇹 · Chiara Signorile-Signorile🇮🇹 · Paolo Torrielli🇮🇹 · Sandro Uccirati🇮🇹
We provide a general method to construct local infrared subtraction counterterms for unresolved radiative contributions to differential cross sections, to any order in perturbation theory. We start from the factorised structure of virtual corrections to scattering amplitudes, where soft and collinear divergences are organised in gauge-invariant matrix elements of fields and Wilson lines, and we define radiative eikonal form factors and jet functions which are fully differential in the radiation phase space, and can be shown to cancel virtual poles upon integration by using completeness relations and general theorems on the cancellation of infrared singularities. Our method reproduces known results at NLO and NNLO, and yields substantial simplifications in the organisation of the subtraction procedure, which will help in the construction of efficient subtraction algorithms at higher orders.
hep-phhep-thJHEP(2018)·66 citations
09*
Sum rules for strong decays of 10 and 27 dibaryon multiplets in broken SU(3) symmetry
G. Sánchez-Colón🇲🇽 · E. N. Polanco-Euán🇲🇽 · C. E. López-Fortín🇲🇽
10 and 27 SU(3) multiplets of hexaquarks states with baryon number B=2, known as dibaryons, are considered. Previous analyses are complemented and sum rules for strong decay amplitudes with SU(3) symmetry violation up to the first order are determined for the 10 and 27 dibaryon multiplets into a baryon octet plus a baryon decuplet and for the dibaryon 27 into two baryon octets.
hep-phInt.J.Mod.Phys.A(2018)·3 citations
10*
Quintessence Saves Higgs Instability
Chengcheng Han🇯🇵 · Shi Pi🇯🇵 · Misao Sasaki🇯🇵
We study a model where quintessence potential $e^{- ξ ϕ}$ coupled to Higgs potential. We calculate the evolution of the quintessence, and track the running of the effective Higgs self-coupling. We find it slightly larger than that of the standard model in the past. Requiring the electroweak vacuum to be absolutely stable in inflationary era, we find a lower bound $ξ > 0.35 \pm 0.05$ , where the uncertainty is mainly from the measurement of the top quark mass. This lower bound, together with the upper bound from the observation for dark energy $ξ ≲ 0.6$ , narrows down the parameter space and makes it possible to test this model in the near future. Interestingly, the bound on $ξ$ , if actually shown to be the case by observation, supports the recently proposed Swampland Conjecture.
hep-phastro-ph.COgr-qchep-thPLB(2019)·94 citations
11*
Forward trijet production in proton-nucleus collisions
Edmond Iancu🇫🇷 · Yair Mulian🇫🇷
Using the formalism of the light-cone wave function in perturbative QCD together with the hybrid factorization, we compute the cross-section for three particle production at forward rapidities in proton-nucleus collisions. We focus on the quark channel, in which the three produced partons -- a quark accompanied by a gluon pair, or two quarks plus one antiquark -- are all generated via two successive splittings starting with a quark that was originally collinear with the proton. The three partons are put on-shell by their scattering off the nuclear target, described as a Lorentz-contracted "shockwave". The three-parton component of the quark light-cone wave function that we compute on this occasion is also an ingredient for other interesting calculations, like the next-to-leading order correction to the cross-section for the production of a pair of jets.
hep-phnucl-thNPA(2019)·27 citations
12*
Masses of the doubly heavy tetraquarks in a constituent quark model
Woosung Park🇰🇷 · Sungsik Noh🇰🇷 · Su Houng Lee🇰🇷
We perform a constituent quark model analysis for the masses of the doubly heavy tetraquark states $T_{QQ}$ after we fix the parameters to fit the masses of the newly observed $Ξ_{cc}^{++}$ and hadrons involving heavy quarks relevant to the stability of these states. We investigate in detail how the relative distances between quark pairs vary as we change the quark content and how they affect the various contributions to the total tetraquark masses. We also find that our full calculations give in general less binding compared to simplified quark model calculations that treat quark dynamics inside the tetraquark the same as that inside a baryon. We trace the main origin to be the differences in the number of relative kinetic energies which increases as one goes from meson, baryon and tetraquarks. We also compare our new results with previous works using less constrained parameters and find that the tetraquark state $T_{bb} (u d b ˉ b ˉ)$ and $T_{bb} (u s b ˉ b ˉ)$ are bound by 120.56 MeV and 7.3 MeV respectively.
↳ nucl-thhep-phNPA(2019)·83 citations
13*
Gauged Wess-Zumino terms for a general coset space
Tomas Brauner🇳🇴 · Helena Kolesova🇳🇴
The low-energy physics of systems with spontaneously broken continuous symmetry is dominated by the ensuing Nambu-Goldstone bosons. It has been known for half a century how to construct invariant Lagrangian densities for the low-energy effective theory of Nambu-Goldstone bosons. Contributions, invariant only up to a surface term -- also known as the Wess-Zumino (WZ) terms -- are more subtle, and as a rule are topological in nature. Although WZ terms have been studied intensively in theoretically oriented literature, explicit expressions do not seem to be available in sufficient generality in a form suitable for practical applications. Here we construct the WZ terms in $d = 1, 2, 3, 4$ spacetime dimensions for an arbitrary compact, semisimple and simply connected symmetry group $G$ and its arbitrary connected unbroken subgroup $H$ , provided that the $d$ -th homotopy group of the coset space $G / H$ is trivial. Coupling to gauge fields for the whole group $G$ is included throughout the construction. We list a number of explicit matrix expressions for the WZ terms in four spacetime dimensions, including those for QCD-like theories, that is vector-like gauge theories with fermions in a complex, real or pseudoreal representation of the gauge group.
↳ hep-thcond-mat.str-elcond-mat.supr-conhep-phNPB(2019)·25 citations
14*
Hair formation in the background of noncommutative reflecting stars
Yan Peng
We investigate scalar condensations around noncommutative compact reflecting stars. We find that the neutral noncommutative reflecting star cannot support the existence of scalar field hairs. In the charged noncommutative reflecting star spacetime, we provide upper bounds for star radii. Above the bound, scalar fields cannot exist outside the star. In contrast, when the star radius is below the bound, we show that the scalar field can condense. We also obtain the largest radii of scalar hairy reflecting stars.
↳ gr-qchep-phhep-thNPB(2019)·18 citations
15*
Do we live in an eigenstate of the "fundamental constants" operators?
John D. Barrow🇬🇧 · Joao Magueijo🇬🇧
We propose that the constants of Nature we observe (which appear as parameters in the classical action) are quantum observables in a kinematical Hilbert space. When all of these observables commute, our proposal differs little from the treatment given to classical parameters in quantum information theory, at least if we were to inhabit a constants' eigenstate. Non-commutativity introduces novelties, due to its associated uncertainty and complementarity principles, and it may even preclude hamiltonian evolution. The system typically evolves as a quantum superposition of hamiltonian evolutions resulting from a diagonalization process, and these are usually quite distinct from the original one (defined in terms of the non-commuting constants). We present several examples targeting $G$ , $c$ and $Λ$ , and the dynamics of homogeneous and isotropic Universes. If we base our construction on the Heisenberg algebra and the quantum harmonic oscillator, the alternative dynamics tends to silence matter (effectively setting $G$ to zero), and make curvature and the cosmological constant act as if their signs are reversed. Thus, the early Universe expands as a quantum superposition of different Milne or de Sitter expansions for all material equations of state, even though matter nominally dominates the density, $ρ$ , because of the negligible influence of $Gρ$ on the dynamics. A superposition of Einstein static universes can also be obtained. We also investigate the results of basing our construction on the algebra of $S U (2)$ , into which we insert information about the sign of a constant of Nature, or whether its action is switched on or off. In this case we find examples displaying quantum superpositions of bounces at the initial state for the Universe.
↳ gr-qcastro-ph.COhep-phPRD(2019)·6 citations
16*
Riemann-Finsler Geometry and Lorentz-Violating Scalar Fields
Benjamin R. Edwards🇺🇸 · Alan Kostelecky🇺🇸
The correspondence between Riemann-Finsler geometries and effective field theories with spin-independent Lorentz violation is explored. We obtain the general quadratic action for effective scalar field theories in any spacetime dimension with Lorentz-violating operators of arbitrary mass dimension. Classical relativistic point-particle lagrangians are derived that reproduce the momentum-velocity and dispersion relations of quantum wave packets. The correspondence to Finsler structures is established, and some properties of the resulting Riemann-Finsler spaces are investigated. The results provide support for open conjectures about Riemann-Finsler geometries associated with Lorentz-violating field theories.
↳ hep-thgr-qchep-phmath.DGPLB(2018)·107 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.